Dendritic spines are the major target for excitatory synaptic inputs in the vertebrate brain. They are tiny evaginations of the dendritic surface consisting of a bulbous head and a tenuous stem. Spines are considered to be an important locus for plastic changes underlying memory and learning processes. The findings that synaptic morphology may be activity-dependent and that spine head membrane ...

Various strains of mouse hepatitis virus (MHV) exhibit different pathogenic phenotypes. Infection with the A59 strain of MHV induces both encephalitis and hepatitis, while the highly neurovirulent JHM strain induces a fatal encephalitis with little, if any, hepatitis. The pathogenic phenotype for each strain is determined by the genetic composition of the viral genome, as well as the host immun...

Compartmental simulations of an anatomically characterized cortical pyramidal cell were carried out to study the integrative behavior of a complex dendritic tree. Previous theoretical (Feldman and Ballard 1982; Durbin and Rumelhart 1989; Me1 1990; Me1 and Koch 1990; Poggio and Girosi 1990) and compartmental modeling (Koch e t al. 1983; Shepherd et al. 1985; Koch and Poggio 1987; Rall and Segev ...

A stable set in a graph G is a set of mutually non-adjacent vertices, α(G) is the size of a maximum stable set of G, and core(G) is the intersection of all its maximum stable sets. In this paper we demonstrate that in a tree T , of order n ≥ 2, any stable set of size ≥ n/2 contains at least one pendant vertex. Hence, we deduce that any maximum stable set in a tree contains at least one pendant ...

Let G H denote the Cartesian product of the graphs G and H. In 2004, Hartnell and Rall [On dominating the Cartesian product of a graph and K2, Discuss. Math. Graph Theory 24(3) (2004), 389–402] characterized prism fixers, i.e., graphs G for which γ(G K2) = γ(G), and noted that γ(G Kn) ≥ min{|V (G)|, γ(G)+n−2}. We call a graph G a consistent fixer if γ(G Kn) = γ(G)+n−2 for each n such that 2 ≤ n...

Pseudorabies virus has a class 2 genome in which the S component is found in two orientations relative to the L component. The L component is bracketed by sequences that are partially homologous; it is found mainly in one orientation, but a small proportion is inverted (J. M. DeMarchi, Z. Lu, G. Rall, S. Kuperschmidt, and T. Ben-Porat, J. Virol. 64:4968-4977, 1990). We have ascertained the role...

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Not long ago, glial cells were thought to have a typical linear rectification of membrane current and lack action potentials, a defining feature of neurons. But these boundaries are blurring. Oligodendrocytic precursor cells (OPCs), identified by expression of the proteoglycan NG2, appear during early postnatal life and maintain the capacity in adulthood to proliferate into oligodendrocytes pro...